The nuclear family is a general model that describes the western trend of people becoming independent and moving away once they reach adulthood then marrying someone, having kids and sustaining that few-person unit until their kids reach adulthood and separate. The key here is independence, typically this implies moving out and getting some career on your own. It was a sort of rite of passage to achieve total independence in this way. The model focuses on a family structure of one married couple and however many kids.
It is viewed as a wholesome and nostalgic trend by many. Some say that everything would be better if we never left the 1950s, they see the death of the nuclear family trend in the modern age and say we just need to bring it back to solve our problems. But I think it is best understood as a part of our decline. The 1950s can't be understood as a golden age that has the solutions to everything. While it was a better time than now, it also predictably leads to all of the problems of the modern world, and for that reason we have to understand it thoroughly and reject it as a solution.
To understand the inferiority of the nuclear family we need to understand the competing unit which was dominant in the most places for the most time prior to the industrial revolution, that would be the extended family, the tribe, the race, the clan, or whatever you would call it. Let's go with tribe.
The tribe is a much larger unit, consisting primarily of many blood relatives from cousins to grandparents and more. Similar tribes which interconnect and cooperate through marriage and oath form into larger entities we would call nations. Tribes live on the same land, collectively harvesting its resources to survive. The main defining element here is the massive amount of familial interdependence, every member is largely dependent on everyone else for survival, as opposed to being dependent on the soulless industrial economy to provide for their needs as in modernity. The difference between community interdependence and what can be called (organizational) industrial dependence can be understood the same as the difference between calling a friend to drive you somewhere vs paying for a ride through a company like Uber. Our goal is to be organizationally independent and tribally interdependent. Independent from those that hate you, dependent on those that love you. It really is that simple.
Within the tribal model the individual is subjected to elders, religious leaders, parents, etc. The individual is accountable to his tribe for both his material and his social needs. When the person who distributes food is also your religious leader, it is very hard to convince yourself to be an athiest. But when you can just buy food from an amoral capitalist entity, space then is created for antisocial behaviors like atheism and hedonism. Tribal interdependence therefore increases group cohesion and incentivizes fruitful cooperation both of which are socially and spiritually fulfilling. In other words, the modern industrial world creates the opportunity to partake in economic activities which are completely amoral and asocial, having zero concern for how that activity interacts with one's group. It is possible to survive without involving yourself with a larger social group at all, which is certainly a leading cause behind the increased rates of depression and loneliness expressed in society today. In a tribal system this dangerous potential doesn't exist. It must be understood that humans, being a social animal, will always benefit from a very unambiguous group association.
Interdependence used to be a dominant organizational force. Due to the rise of technology its incentives have been made obsolete by industrial economic incentives. These incentives are also related to government policy, if you've ever tried to build a second house on your piece of land you'll know how hard it is to get building permits. The state doesn't want you to keep an extended family on a single large piece of land partly because it knows that smaller social units have to engage in more economic activity to satisfy their needs and are easier to micromanage. The nuclear family then is a step in the decline of that mutual dependence that holds us all together, the final step being the excessive individualism we see in the 21st century. With the nuclear family the tribe is broken up into tons of smaller units of individual married couples and their kids. These units largely exist because of the economic incentive to be efficiently moved about and placed in jobs and locations decided by the market.
The capitalistic rationalist might say "There's no logical difference between satisfying a need through the industrial system and satisfying it through group cooperation since in either case the need is satisfied, so just use the industrial economy cause it's more convenient.", this is the position of someone who spends too much time being an antisocial liberal philosophy/economics nerd that is only concerned with shallow materialistic efficiency. They are stuck in a quantitative mindset, unable to comprehend why very direct group cooperation increases quality of life through positive social and moral stimuli. The fact is that it is good to satisfy your moral duty by helping your fellow man. Think about the social and moral superiority of contributing labor to your family wheat field and collectively enjoying its fruits versus just buying bread from walmart for yourself using money you made by laboring for some random businessmen. In tribal living, even the most basic of survival tasks becomes a highly motivated moral and social behavior, whereas in the industrial world every survival need is satisfied by the complex organization of mutually selfish amoral individuals.
The smaller unit size and relative independence that a nuclear family has from their tribal influences means they are more capable of rejecting or just forgetting valuable traditions. If traditions are not upheld actively by dedicated men then it is very easy to forget why they existed in the first place. The tribe will give some members the duty of enforcing tradition, so that others may focus on their jobs and families. When you leave the tribe your proximity to all of that influence is lost and you will be less able to preserve tradition on your own. While a smaller unit's extended family, religious leaders and other affiliates may exist and may interact with them sometimes, they do not share the same land or work the same jobs, they do not have constant close proximity or presence. This means that fewer instances of positive influence can occur. Therefore, the smaller social unit will be more susceptible to the abundant evil influences in the world today. This is why the nuclear family collapsed in recent years and gave way to the more extreme independence of individualism. The same decline that caused the nuclear family in the first place has grown out of it and into something even worse.
Some may wonder why some extremely individualistic, hedonistic and selfish groups such as the LGBT movement are very organized and tribal. This points to the truth that tribalism is in our nature, it is instinctual. It then is very easy for the media and powerful institutions to form tribal affiliations around evil subjects like that. It is only those who wish to specifically practice very traditional european religious tribalism who are denied that organizational ability through psyops and media smear campaigns. But this effort is necessarily a massive struggle for them because it is attempting to supress a strong natural tendency.
Those who are very observant of their spiritual and social needs will at some level recognize their need for a grander group association, usually this results in them going to church. Christianity is the only real prominent tribe left in the west, as great as that is it still lacks the level of demanding and fulfilling involvement that a traditional tribal life does. The modern church doesn't do much to keep you out of the industrial system that caused the problem in the first place and it doesn't generate very much interdependence. This leaves room for us to reimagine our approach. An ambitious creative project must be done where a sort of neo-tribalist christianity is invented and marketed that is capable of generating that much needed close proximity and demanding mutual dependence by transcending the incentives of the modern economic machine, the primary goal would be convincing like-minded people to move to rural religious areas. Geographically, a rural area is less able to utilize distant industrial luxuries, encouraging localized interdependence and cooperation as an alternative.
To achieve this on a massive scale is a lot to ask and will require great institutional change from the highest power centers. A new type of information warfare would need to be utilized which will create organizational energy and consensus despite the CIA psyops and media manipulation that will try to stop it, likely only achievable through the abolishment of free press. The incentives of global finance will have to be overcome, a ban on usury would be necessary. The incentives of the industrial economy would have to somehow be made generally obsolete. A project of this sort may seem unlikely, but the fact is that it is in the interests of a very large amount of disaffected white people, with their popular support the possibility for a power grab does exist, popular support is always appealing to power centers. This would require our tribe to have a lot of intelligent, creative, high agency and financially well off people to brainstorm, fund and execute a strategy for huge growth, those people will only join if people like you go out and convert them. Should that larger project arise, whatever its form, you must also be ready to contribute to it for the sake of your tribe. This is the most likely way I can imagine a somewhat large scale revival of proper tribalism in the modern world, as unlikely as it may seem given the current situation.
In the meantime you can achieve this sort of lifestyle for yourself and preserve your tribal well-being by moving into a smaller rural community and going to church. Encourage others to do the same. Good luck.